Very many thanks for this.
I too had long forgotten this game, and having become bored to death by Sudoku, this is just the kind of 'brain-training' I needed.
Wonderful stuff. The program's GUI has a few glitches that would not get past the major software houses' QA Dept., but it's freeware for goodness sake.
Five stars from me, despite a couple of rough edges.

I had long forgotten that this game existed as a board game. It was a favorite of mine before DVD players and iPods, could take the boredom out of a cross country flight.
SMasterMind is a great adaptation of the original. You can make it as difficult or as simple as you wish by increasing the number of colors and rows. It's a matching game where you try to guess the hidden row of colors by getting white indicators if you have the right color in the wrong place and black if you have the right color in the right place.
I'd like to see a bigger board size and glossier colors maybe metallic or "candy" colors. I would expect to pay for the game at that point.
As 1.2.4 is now, it's worth more to me than the games I've paid $29-$59 for.
Installation is no problem drag into apps, and the game is stable on my G4 iMac, G4 PowerBook and MacBookPro. I have spent a lot of enjoyable time playing SMM, it ranks up there with Quinn as addictive games I wouldn't want to be without.
I'm embarrassed I sound like a shill, but honestly I have no idea who the developer is.

MasterMind App is great. I played it 30 years ago and just found it on MacUpdate. It is great for stress relief, takes your mind off everything except the game. Thanks for making it available FREE! It seems to work on all Macs, even my Intel. Great while waiting for flights.